Pernicious Anaemia Society

help with diagnosis

Hi everyone,

I have recently been diagnosed with low B12 and I am currently having injections every other day. I have been exhausted to the point where I have fallen asleep at my desk at work, I have pins and needles in my left arm and leg, I faint if I over do it, diarrhoea , vomiting, foggy head, dizziness, headaches, which is just awful

I saw a GP a couple of weeks ago who based on the low B12 and my symptoms thinks I have pernicious anaemia. I have always taken multi vitamins everyday and eat plenty of fish meat dairy etc each week so he thinks it is totally unrelated to a diet deficiency as do I. However, we are waiting for the antibody blood test to confirm PA as my full blood count and other parameters all came back normal so low B12 and my symptoms are all that we have to go on so far.

The GP has already advised me that if the antibody results come back normal then because of current guidelines the B12 injections will be stopped as they can only be given long term in confirmed cases of PA. he said basically if all parameters are normal other than low B12 it will just be assumed that it is diet related.

The thought of this fills me with dread as even with the injections my latest B12 level was still really low and had only marginally improved from my first blood test 3 weeks ago, if they stop them I dread to think what's going to happen symptom wise.

My concern is having had a look at the forum and PAS website I noticed that other people have been in a similar situation where all blood parameters have come back as normal and low B12 is the only confirmed problem.

I guess my question is if my antibody blood test does come back normal and all other parameters are normal as well, and I am getting plenty of B12 in my diet and my levels are still low even after injections, what else can I do to get a diagnosis confirmed, and get the right treatment are there other tests I should be pushing for, or should I be referred to a specialist.

any help greatly appreciated, thank you

5 Replies

Your doctor is wrong about the guidelines. I know someone will be along shortly to provide more specifics on the guidelines. If your antibody tests come back negative you should still be treated for IF negative PA. It is important to know that the antibody tests are not 100% accurate. In fact the intrinsic factor antibody test is only about 60% accurate at identifying people who have PA. If you test positive for intrinsic factor antibodies it means you definitely have PA, but if you test negative it doesn't rule out having PA. It just means you may be part of the 40% who have it but never test positive for the antibodies.

B12 deficiency can have multiple causes. It sounds like your doctor believes that there are only two causes; either diet or PA. It's possible that your doctor is just lumping all non-diet related causes of B12 deficiency together under the term of PA, but that would also be incorrect. Some people become deficient because of other medications they are taking (such as metformin for diabetes), or from having gastric bypass surgery, celiac disease, or due to genetic mutation. It can also happen in alcoholics and people who abuse nitrous oxide. There are many possible causes. No matter the cause, the deficiency should still be treated.

Your doctor should re-read the guidelines and should also remember that the guidelines are just guidelines. Individual patients may need an individualized treatment approach. He or she should be prepared to deviate from the guidelines when necessary.

1 like

Assuming you are based in UK - as Galixie says your GP is so wrong about basing your treatment on the PA test - which is as Galixie says - not a good indicator of whether you have PA or not as it isn't very accurate.

If the problem isn't diet then it will be an absorption problem. PA is just one possible absorption problem

Others include

- gastric surgery affecting the ileum (where B12 is absorbed)

- genetic abnormalities affecting the ileum

- lowering acidity levels as you get older (body requires a certain level of acidity to absorb B12)

- drug interactions (including a lot that are used to treat early indicators of a developing B12 problem, or even symptoms of B12 - as well as drugs used to treat other conditions.

None of these underlying problems is going to be corrected by correcting the initial B12 deficiency they have caused and it will just recur.

The NICE guidance is to treat with injections unless it can be demonstrated that the problem is diet

recommendation makes no reference to any particular cause of the deficiency - only distinguishes between dietary and other

potentially confusing as it doesn't mention that the real difference in treatment is between diet and absorption ... though arguably a drug interaction might be a case where supplementation for life is not necessary.


He is incorrect...... BCSH guidelines clearly state that you can be IF neg PA. I'm afraid many doctors are just not up to date with B12 deficiency.

Google the BCSH guidelines and print them off....... There is a very useful chart there which shows how to treat, and will put him right. If he insists on stopping your injections you must change GPs or ask to see a haematologist. There may be a wait for that though.

1 like

Hopefully you are in the UK as my commnets relate to the UK.

" if the antibody results come back normal then because of current guidelines the B12 injections will be stopped as they can only be given long term in confirmed cases of PA."

Your GPs comment is innaccurate.

Google "BCSH Cobalamin and Folate guidelines" These were updated in 2014. It's a long document but well worth reading all of it. Have a look at page 29 which is a diagnosis flowchart. It refers to antibody negative PA so makes it clear that it is still possible to have and confirm PA even if antibodies are negative. The chairman of the PAS tested negative on more than one occasion for antibodies before testing positive.

Has your GP got a copy of the BCSH document? The PAS have a useful summary of this document in the library section of their website.

Is it a test for IFA (Intrinsic Factor antibodies) that you are waiting for? This test is unreliable in a large percentage of cases. The PAS will tell you more about this as will BCSH guidelines. MMA, Homocysteine and Active B12 tests may be more reliable but if you are already supplementing with B12 then the tests results could be unreliable. I personally wasted a lot of money on private tests and think the results were compromised by my B12 supplementation.

Another useful test that is rarely done on the NHS but I think can be done privately is a "blood smear" aka "blood film". This looks for abnormally shaped blood cells.

I'd strongly recommend you ring the PAS. You don't have to be a member to speak to them. If you leave a message they will get back to you. Head office: 01656 769 717

Other useful links/books

Has your GP got a copy of the summary points of this article? It makes it clear that symptomatic patients should be treated to prevent neuro damage even if blood results are normal.

This emphasises the importance of not delaying treatment in symptomatic patients even if test results are normal. Has your GP got a copy of this? This website has a useful section on writing to your GP.

"or should I be referred to a specialist. "

Do you have any neuro symptoms? If yes, is your GP aware of all of them?


The treatment for patients with PA or B12 deficiency with neuro symptoms is more intensive.

Your GP can look in his/her copy of the BNF (British National Formulary) at Chapter 9 Section 1.2. The BNF is copyrighted. It is possible to get your own copy of the BNF.

My understanding is that people with B12 deficiency or PA with neuro symptoms should get an injection every two days until they stop improving ( that could mean loading doses for a period of several weeks even months) then they should get an injection every two months. I also think that patients with B12 d or PA with neuro symptoms are supposed to be referred to a haematologist.

"as my full blood count and other parameters all came back normal"

Did the GP check your ferritin (iron) and folate levels? You need to have good levels of folate, ferritin and B12 as the way they work in the body is closely interlinked.

Do you have paper copies of your results?

I found it helpful to always get paper copies of my results. I was told results were normal and then found some weren't when I got the copies, the surgery will probably charge for this. It can also be helpful to see how close you are to the edge of the range even if your results are normal range.

Low iron (ferritin) makes your red blood cells smaller. Low B12 and/or folate makes your red blood cells bigger. If you have both low ferritin and low B12 and/or folate then your MCV and MCH on your full blood count may appear normal and your GP might miss potential problems.

High MCV and high MCH can indicate a macrocytic or megablastic anaemia.

It can be useful to find out the guidelines in your local NHS area.

Some regional guidelines may not have been updated with the recent guidance from BCSH guidelines and this could explain your GPs comment about stopping B12 injections.

Have a look on your local NHS website. Put "B12 deficiency management guidelines" in the search. If you can't find them on the website, you could submit an FOI request (Freedom of Information). Just put FOI in searchbox. You could also contact your local CCG (Clinical Commisioning Group) and ask what guidelines are being followed for the treatment of B12 deficiency in your area.

One word of warning is that patients who ask lots of questions can sometimes be labelled as difficult. I think it is helpful to take someone with you who understands your illness, is supportive and who has read current guidance and may be able to ask questions on your behalf if you are unable to.

1 like


These books are also useful in my opinion.

Could It be B12 by Sally pacholok

Pernicious Anaemia ; The forgotten Disease by Martyn Hooper

Living with Pernicious Anaemia by Martyn Hooper

The one above made me cry it was like reading about myself.

If you find Martyn Hooper's books useful, he is publishing a third one later this year.

Details on his blog. Some of teh blog posts are very interesting


You may also like...